When drilling plastic it is important to know how hard the plastic is. To achieve a good drilling result, the following basic rule should be observed.
Soft plastic = low drill bit speed and little pressure when drilling
Hard plastic = higher drill speed and more pressure when drilling
Tip! If the drill speed is too high and too much pressure is applied, the plastic can become hot and melt during drilling. In order to avoid this, water with a little detergent should be used for cooling. A few drops on the drilling site and on the drill are sufficient here.
For all plastics, ordinary HSS metal drills are best suited. They have a very high cutting performance and a sharp tip. When drilling in plastics, you should always use a relatively new and sharp drill bit. If an old or blunt drill is used, the workpiece becomes very hot during the drilling process and the drilling result is usually not satisfactory. The best result is obtained with a new HSS metal drill, which you can buy here at a reasonable price.
If you want to drill a larger hole, e.g. in a rain barrel, use a so-called step drill, shown on the left side of the picture. With this drill you get a big clean hole also in thin plastics to attach e.g. afterwards a water tap or connection. You can buy a good and cheap step drill here..
Tip! To prevent the drill from slipping off, it is advisable to mark the drilling location with a center punch or nail.